The preparation of chloro-s-triazine triones such as trichloro-s-triazine trione or dichloro-s-triazine trione is well known in the prior art.
One method for producing chloro-s-triazine trione is described in U.S. Pat. No. 2,969,360 issued Jan. 24, 1961. In this process, cyanuric acid (also known as s-triazine trione) is fed along with aqueous alkali metal hydroxide (in molar ratio to the cyanuric acid equal to the number of chlorine atoms per molecule of the desired product) and chlorine to an aqueous reaction zone which is maintained at a pH near 3.5. The feed ingredients are added in essentially stoichiometric proportions. Crude chloro-s-triazine trione precipitates from the solution, to form a slurry. The product slurry is filtered to separate the crystalline product from the mother liquor, and the crystalline product is dried.
The crystal properties of the chloro-s-triazine trione have a marked effect on the trouble-free operation of the process. It is preferred that the crystals of chloro-s-triazine trione be as large as possible. The crystal habit can also effect the ease and efficiency of filtration and drying of the product. The crystal habit of the product can also affect its chlorine stability. Crystal modifiers can be used to enhance the crystal properties of the product to increase its crystal size and change its crystal habit to improve the properties of the product.
Various substances have been proposed in the patent literature to act as crystal modifiers in the production of chloro-s-triazine triones. U.S. Pat. No. 3,120,522 issued Feb. 4, 1964 uses a chlorinated hydrocarbon with from 1 to 6 carbon atoms and not more than one hydrogen atom per molecule. U.S. Pat. No. 3,453,274 issued July 1, 1969 uses alkali metal sulfates or alkali metal alkylarylsulfonates. U.S. Pat. No. 3,941,784 issued Mar. 2, 1976 uses a small amount of polyoxyethylene, polyoxypropylene, or copolymers of polyoxyethylene and polyoxypropylene. U.S. Pat. No. 4,087,608 issued May 2, 1978 uses alkylated diphenyloxide disulfonic acid or alkali metal salts thereof.
The object of this invention is to provide a chloro-s-triazine trione product having improved properties, as a result of enhanced crystal properties.